Only suggestion I have to see if it might be the panel or the GPU (could be something else), is for someone that is experiencing this and has access to a PC/mac, could you run the 27" as a display. I know only some of you will have adapter for this, but this might be a good way to work out if it is the GPU or panel that is having issues. In theory if you run the 27" as a display only it will not use the imac GPU.

It was impossible to reproduce. I could work for hours on the computer and then suddenly it would flicker randomly with a band of horizontal static bars about 3 inches thick momentarily or, alternatively, it would black out for a fraction of a second. This could happen up to once every 5-10min.

I was able to return the computer to the Apple Store, who were reasonable enough to waive the restocking fee.

I suspect that this is a hardware issue. I almost hope that it is - that way it will be more common and fixed sooner.

I think there is anybody with the same problem. Since this morning my display of my 27" iMac show the menubar in the middle of the display and above there are a lot of vertical lines in multi colors. Now I think this one is not a problem with the driver, I hoped this first, I think there is a problem with the graphic chip.

First it was a sporadic flickering like your iMac but now the iMac - the display - goes more and more defect.

At the moment I take a backup of my HD, well - its better to bring the iMac back.

Got a new 27" iMac yesterday and had no problems whatsoever all night.. After waking the iMac from sleep I began to see this flickering problem. The machine was not hot whatsoever so I dont think the issue is heat related. One thing I did was manually put the machine into sleep mode and waking it up again. Since doing so, I havent seen the problem. Something is telling me that this is a software issue. I wish apple would confirm this before the 14 day return period is up.

Just bought the 27" yesterday and noticed the flickering while Firewire transfering my older 20" imac over to the new one. I thought it may have been the LED adjusting or something. The iMAc was cold, first time turned on.

I let it sleep overnight, and once again, while cold, I turned it on and the flickering and menu bar on the top portion of the screen is happening. It does this for roughly five minutes then it goes to normal? I have no idea whats wrong and its annoying and scary... software or hardware? I'll wait a few days before taking it in, but this needs a fix ASAP. I can imagine how its going to upset many.

Forgot to add: I tried taking a screenshot while it was in the middle of this process, and the screenshot shows a normal desktop, as if nothing changed (the horizintal static was not on it). I'm not sure how the system takes screens, but I'm not liking the fact that the screenshot was normal... this points to an unfortunate hardware issue. I hope I am wrong.

Just started getting the same issue... wow. Google search pulled up this forum. Seems to be getting worse. Quick flicker of bar at the lower half of the screen. No real way to reproduce. Have tried restarting and also sleep.

This was my first Mac, purchased a few days ago. Maybe I should sign up for AppleCare now...

I received my 27" iMac three days ago and ever since i got it out of the box and turned it on it has done the same as the video shows.

Last night i watched a 30 min programme on BBC iPlayer and the 2-3 inch white lines kept popping up every few seconds horizontally across the screen. The screen also went black momenterally on 6 occasions.

I cannot believe after three days that this problem is so bad. I spome with Apple this morning on the Apple Care line and they told me to:1. Shut down and take out power cord for 20 secs then turn back on.2. Shut Down and then hold down "D" when turning back on which performed a hardware test...Both had no effect.

Luckilly i am still within the 14 days of recieving my iMac and they are sending out a replacement but i am worried that this machine will have the same problems...

Is anyone happy with theres and is anyone not experiencing this problem... There seems to be a big issue here???

Same problem here, the momentary black screen and the flickering. Seems to be very sporadic, won't happen for a few hours and then seems to happen every 20 seconds or so. Also the computer sometimes won't wake from sleep, not sure if its related, but if I recall correctly the first time it happened was after it was difficult waking it from sleep.

Spoke to apple today, ran me through the regular steps (power cord out for 20 secs, etc) and was fine for a few hours but has now started again. This is my first desktop mac, and I'm still within my 14 day 'grace' period......should I be tempted by a windows 7 machine...?

Just received my iMac 27" from Shanghai. Screen has flickering and going black. Have called Apple tech support to begin replacement process. Makes me question the life span of the LED screen technology. Is this going to be my screen experience 1 day after the AppleCare runs out? I hope Apple addresses quickly.

More Like This

Retrieving data ...

This site contains user submitted content, comments and opinions and is for informational purposes only.
Apple may provide or recommend responses as a possible solution based on the information provided; every potential issue may involve several factors not detailed in the conversations captured in an electronic forum and Apple can therefore provide no guarantee as to the efficacy of any proposed solutions on the community forums.
Apple disclaims any and all liability for the acts, omissions and conduct of any third parties in connection with or related to your use of the site. All postings and use of the content on this site are subject to the Apple Support Communities Terms of Use.